Quenching Limits and Materials Degradation of Hydrogen Diffusion Flames
Total Page：16
File Type：pdf, Size：1020Kb
ABSTRACT Title of Document: QUENCHING LIMITS AND MATERIALS DEGRADATION OF HYDROGEN DIFFUSION FLAMES Nicholas R. Morton, Master of Science in Fire Protection Engineering, 2007 Directed By: Assistant Professor, Peter B. Sunderland, Department of Fire Protection Engineering This study examines the types of hydrogen leaks that can support combustion and the effects on various materials of long term hydrogen flame exposure. Experimental and analytical work is presented. Measurements included limits of quenching, blowoff, and piloted ignition for burners with diameters of 0.36 to 1.78 mm. A dimensionless crack parameter was identified to correlate the quenching limit measurements. Flow rates of 0.019 to 40 mg/s for hydrogen, 0.12 to 64 mg/s for methane, and 0.03 to 220 mg/s for propane were studied. Hydrogen quenching limits are found to have lower mass flowrates than those of methane and propane. Hydrogen blowoff mass flowrates are found to be higher than methane and propane. Materials degradation experiments were conducted on 1080 – 1090 carbon steel, 304 and 316 alloys of stainless steel, galvanized 1006 – 1008 carbon steel, aluminum alloy 1100, and silicon carbide fibers. Exposure to hydrogen flames is found to severely degrade aluminum alloy 1100. Noticeable corrosion is present on 304 and 316 stainless steel, galvanized 1006 – 1008 carbon steel. Silicon carbide fibers perform relatively similarly for hydrogen and methane flame exposure. QUENCHING LIMITS AND MATERIALS DEGRADATION OF HYDROGEN DIFFUSION FLAMES. By Nicholas R. Morton Thesis submitted to the Faculty of the Graduate School of the University of Maryland, College Park, in partial fulfillment of the requirements for the degree of Master of Science 2008 Advisory Committee: Assistant Professor Peter B. Sunderland, Chair Associate Professor André Marshall Associate Professor Frederick W. Mowrer © Copyright by Nicholas R. Morton 2007 Dedication To my Grandfather. ii Acknowledgements This work was supported by NIST (Grant 60NANB5D1209) under the technical management of J. Yang. I would like to express my gratitude to my advisor, Dr. Peter Sunderland, for his guidance, support, and encouragement. It has been my privilege. I also thank my friend, Dr. Ezekoye at the University of Texas, for introducing me to the field of all things fire. His enthusiasm and guidance while I considered the pursuit of this degree were invaluable. I thank my advisory committee, Dr. André Marshall and Dr. Frederick Mowrer, for their time and input. The faculty of the Department of Fire Protection Engineering for the encouragement and support, and the friendly atmosphere that is the hallmark of this wonderful program, I cannot thank you enough. Special thanks to the staff of the FPE office, specifically Patricia Baker and Allison Spurrier, who willingly take care of the hardest part of this whole process, the paperwork. I would also like to thank my colleagues, for their assistance, reminders, and friendship. Specifically K.B. Lim, Vivien Lecoustre, and Chris Moran, were instrumental in the completion of this work. I especially thank the Fire Protection community back home in Texas for insisting I needed this degree, my family and friends who supported my decision, and my nieces and nephews, for allowing me to go so far, for so long. iii Table of Contents Acknowledgements......................................................................................................iii Table of Contents......................................................................................................... iv List of Tables ................................................................................................................ v List of Figures.............................................................................................................. vi Nomenclature.............................................................................................................. vii Chapter 1: Introduction................................................................................................ 1 1.1 Basics of Hydrogen............................................................................................. 2 1.2 Sources of Hydrogen........................................................................................... 2 1.3 Hydrogen Safety ................................................................................................. 3 1.4 Literature Review................................................................................................ 5 Chapter 2: Phenomena ............................................................................................... 10 2.1 Quenching......................................................................................................... 10 2.2 Standoff Distance.............................................................................................. 10 2.3 Blowoff ............................................................................................................. 11 Chapter 3: Quenching and Blowoff Limits................................................................. 13 3.1 Crack Parameter................................................................................................ 13 3.2 Experiments ...................................................................................................... 17 3.2.1 Quenching Limit Experimental Setup and Procedure ............................... 17 3.2.2 Blowoff Experimental Modifications ........................................................ 20 3.3 Quenching and Blowoff Results ....................................................................... 21 Chapter 4: Corrosive Effects of Flames...................................................................... 31 4.1 Burner Tube Test .............................................................................................. 31 4.2 Wire and Fiber Experiments ............................................................................. 34 4.3 Wire and Fiber Test Results.............................................................................. 37 4.3.1 Stainless Steel Alloy 304 ........................................................................... 37 4.3.2 Stainless Steel Alloy 316 ........................................................................... 39 4.3.3 Aluminum Alloy 1100 ............................................................................... 39 4.3.4 Galvanized 1006-1008 Carbon Steel ......................................................... 40 4.3.5 SiCO Fiber ................................................................................................. 41 Chapter 5: Conclusions............................................................................................... 44 5.1 Quenching and Blowoff.................................................................................... 44 5.2 Materials Effects ............................................................................................... 45 Bibliography ............................................................................................................... 46 iv List of Tables Table 3.1 BEX Burner Summary 18 Table 3.2 Rotameter Summary 20 Table 3.3 Selected Fuel Properties 26 Table 3.4 Percentage Change in Fuel Flowrates 29 Table 4.1 Wire and Fiber Materials Summary 34 Table 4.2 SiCO Fiber Details 36 v List of Figures Fig. 2.1 Heat Loss to the Boundary 10 Fig. 2.2 Standoff Distance 11 Fig. 2.3 Anchoring Points 12 Fig. 3.1 BEX Burner Schematic 17 Fig. 3.2 Flow System Schematic 19 Fig 3.3 Plot: Hydrogen, mfuel vs. Diameter 22 Fig 3.4 Plot: Methane, mfuel vs. Diameter 23 Fig 3.5 Plot: Propane, mfuel vs. Diameter 24 Fig 3.6 Plot: Hydrogen, u0 vs. Diameter 26 Fig 3.7 Plot: Methane, u0 vs. Diameter 27 Fig 3.8 Plot: Propane, u0 vs. Diameter 28 Fig 4.1 Hydrogen and Methane Flame Comparison Image 32 Fig. 4.2 Long Term Burner Pre-Test Image 33 Fig 4.3 Long Term Burner Post-Test Image 33 Fig. 4.4 Stainless Steel Alloy 304 during the short term test 38 Fig. 4.5 Stainless Steel Alloy 304 at the end of the long term test 38 Fig. 4.6 Stainless Steel Alloy 316 during the short term test 39 Fig. 4.7 Aluminum Alloy 1100 at the end of the short term test 40 Fig. 4.8 Aluminum Alloy 1100 at the end of the long term test 40 Fig 4.9 Galvanized Carbon Steel at the end of the short term test 41 Fig. 4.10 SiCO fiber during the short term test 41 Fig. 4.11 SiCO yarn after one hour 42 Fig. 4.12 SiCO yarn after 13 hours 43 vi Nomenclature a Dimensionless fuel-specific empirical constant CP Dimensionless crack parameter d Burner inside diameter D0 Mean diffusion coefficient h Standoff distance HRR Heat generated by the flame Lb Burner length Ld Flame standoff distance Lf Diffusion flame length Lq Quenching distance Mfuel Gas jet mass flowrate Qf Volumetric fuel flowrate Qwall Heat transferred to an area Re Reynolds number u0 Average fuel velocity in the burner YF,stoic Stoichiometric fuel mass fraction ∆p Pressure drop across the burner ρ Fuel density µ Fuel dynamic viscosity vii Chapter 1: Introduction There is a need and a desire for alternative fuel and energy technologies in the near future [1]. Hydrogen is attractive because of the clean nature of its combustion processes, as well as the potential for a clean and renewable hydrogen source. The use of hydrogen lacks the level of investigation and refinement of more common fuels like methane and propane. There are many unknowns related to widespread hydrogen use. This study aims to determine